1. Field of the Invention
The present disclosure relates to the improved performance of weapons and more specifically to increasing the cooling of firearm barrels.
2. Description of the Related Art
Firearms are used to discharge a projectile, such as a bullet, at a target. Firearms include rifles, shotguns, pistols, and revolvers with integral or removable barrels. A cartridge or round is first loaded, manually or automatically, into a proximal chamber at the breech end of the barrel; then, a firing pin strikes a primer in the base of the casing, igniting an explosive charge of expanding gases that propel the bullet out of the top of the casing. The bullet then travels within a central, longitudinal bore in the barrel and exits a distal muzzle end. A series of helical lands and grooves in the bore wall introduce a twist about the bullet's central axis, vastly improving its accuracy. The lands and grooves are known as rifling.
The expanding and combusting gases within the barrel's bore generate heat energy, which, in turn, raises the temperature of the surrounding barrel material. In most cases, barrels are made of high strength, carbon steel to withstand the high pressures. Firing many rounds in rapid succession can raise the temperature of some barrels to over 600 degrees Celsius (1100 degrees Fahrenheit). Heat radiating from the top of the barrel can interfere with the down range view of a target through the sights. A large temperature gradient can also occur along a barrel's longitudinal length, causing the barrel to deflect slightly, thus negatively affecting the firearm's accuracy. Excessive heat can also lead to a phenomenon known as cook-off. This occurs when the chamber of the barrel becomes so hot that, when a round is inserted into the chamber and the firing is ceased, the primer auto-ignites, causing a bullet to discharge from the muzzle without the trigger ever being pulled.
In some instances, barrels must be allowed to cool for a period of time or a cool replacement barrel must be interchanged before continued firing can continue. In other instances, the rate of fire must be rationed to ensure that the barrel doesn't overheat. Neither of these situations is ideal when a soldier is facing an enemy insurgent in a hostile firefight.
U.S. Pat. No. 2,935,912; U.S. Pat. No. 4,753,154; and US Patent Application Publication Number 2007/0039224 teach conductive cooling of barrels through contact with a liquid coolant medium such as water. U.S. Pat. No. 4,982,648; U.S. Pat. No. 5,062,346; U.S. Pat. No. 7,707,763; US Patent Application Publication Number 2004/0119629; and US Patent Application Publication Number 2006/0207152 teach convective cooling of barrels by directing a stream of ambient air through grooves, channels, shells, and shrouds disposed about the barrel. U.S. Pat. No. 4,638,713; U.S. Pat. No. 5,400,691; and U.S. Pat. No. 6,298,764 teach wrapping of barrels with insulating materials to reduce their infrared signature, equalize the temperature gradient along the barrel's length, and suppress the muzzle flash.
Despite the various teachings disclosed in the prior art, further enhancements to barrel cooling technology are needed.